1. Field of the Invention
The present invention relates to a terminal lead-out structure and a solar-cell apparatus provided with such structure. More particularly, the invention relates to a highly reliable terminal lead-out structure having a good operativity in leading out a terminal, and relates to a solar-cell apparatus provided with such structure.
2. Related Background Art
In recent years, the consciousness of environmental problems has increasingly intensified and widely spread all over the world. Particularly, apprehensions are sensed more seriously with respect to the warming phenomena of the earth brought about by the CO2 emission. The provision of clean energy is more in demand increasingly. At present, a solar cell is regarded as a source of clean energy because it is safe and easy to handle.
There are various modes of solar cells. As typical ones, the following can be named: (1) a crystal silicon solar cell, (2) a polycrystalline silicon solar cell, and other crystalline silicon solar cells, (3) an amorphous silicon solar cell, (4) a copper indium selenide solar cell, and (5) a compound semiconductor solar cell, among others. Conceivably, it is possible to produce, among those solar cells, thin filmed crystalline solar cells, compound semiconductor solar cells, and amorphous silicon solar cells on a large scale at comparatively low costs. Therefore, research and development on them have been in progress in many fields in recent years.
Usually, the solar cell elements, which generate solar power and constitute solar cells, are buried in a filling agent, such as EVA (ethylene-butyl vinyl copolymer) or the like. Also, each of the solar cell elements buried in such filling agent is sandwiched between a surface coating material and a rear side reinforcement material. Each of them is used as a module (a solar cell module). In this case, glass or weatherability film, such as fluororesin film, is adopted as the surface coating material. Also, as the rear side reinforcement material, the following is used, among others: a weatherability and damp-proof film structured by sandwiching aluminum foil with weatherability films; a thin steel plate such as uncoated galvanized steel plate; a steel plate coated by polyester resin or acrylic resin in consideration of its bending capability, hardness, and others; or a plastic plate.
As an output terminal of such solar cell module, there has been conventionally used, among others, a screw fixation type, a lead line type, or a socket type. For any one of them, there is often produced a terminal lead-out structure, such as a terminal box having a water-proof structure for insulation.
Also, for the structure of the terminal lead-out unit of a portable solar cell module, there is, among others, just a simple structure wherein soldered terminals are buried in a filling agent or wherein such terminal unit is covered by a thermal contraction tube or a rubber cover, which dually serves as an edge cover of the module.
Now, as described above, a solar cell is generally used as a clean and non-exhaustive source of energy supply. Also, research and development is carried on in various ways, including an active development of solar cell module well suited for the installation on the ground as well as on the roof.
Particularly, with respect to the installation on the roof, it is useful to develop a solar cell module that functions dually as a roofing material, such as the one being formed integrally with a roofing material, so as to lower the costs for promoting use of solar cells more in the future.
However, if the terminal lead-out structure of a solar cell module is such that the soldered portions are simply covered by insulators, there is a problem that the tension exerted on the terminal lead line is directly carried over to the electrode lead-out unit of the solar cell module.
The other problems encountered in this respect are that the fluororesin film used as the surface coating material for a solar cell module and the filling agent are not adhesively bonded well so that rainwater permeates through the interface between them, the terminal box cannot be fixed on the light receiving surface side of a solar cell module, or some others.
It is an object of the present invention to provide the terminal lead-out structure of a solar cell module having a good water-proof capability, a good strength against physical load, and a high durability, and also, to provide a solar-cell apparatus having such structure.
It is another object of the invention to provide the terminal lead-out structure of a solar cell module having a good adhesive operativity and a high reliability, and also, to provide a solar-cell apparatus having such structure.
It is still another object of the invention to provide the terminal lead-out structure of a solar cell module having a beautiful outer appearance, and to provide a solar-cell apparatus having such structure.
It is a further object of the invention to provide the terminal lead-out structure of a solar cell module of a simple, inexpensive, and space saving screw fixation type, and also, to provide a solar-cell apparatus having such structure.
In consideration of the problems encountered in the conventional technique described above, the present invention is designed. It is an object of the invention to provide a terminal lead-out structure for use with a solar cell whose operativity and uniformity of operation are excellent at the time of installation, and whose operation costs are low and reliability is high once the installation is completed, and also, to provide a solar-cell apparatus having such structure.
In consideration of the problems encountered in the conventional technique described above, it is another object of the invention to provide the terminal lead-out structure of a solar cell module having a good water proof capability, a good operativity, and a high reliability, and also, to provide a solar-cell apparatus having such structure.
In consideration of the problems encountered in the conventional technique described above, it is still another object of the invention to improve the operativity of a solar-cell apparatus at the time of its post processing and installation.
It is a further object of the invention to provide a terminal lead-out structure comprising a lead line drawn out from the electrode lead-out unit on the light receiving side of a solar cell module having a weatherability film treated to discharge electricity at least on a part of its light receiving surface side; and a hollow structure arranged on a part where the electricity discharge is treated for the weatherability film for the insulating protection of the electrode lead-out unit, here, the interior of the hollow structure being filled with a filling agent, and also to provide a solar-cell apparatus having such terminal lead-out structure.
It is still a further object of the invention to provide a terminal lead-out structure having a hollow structure for the insulating protection of the electrode lead-out unit of an apparatus, wherein an extrusion is arranged at least on a part of the surface of the hollow structure to face the apparatus, and such extrusion is adhesively bonded to the apparatus by the application of an adhesive agent, and also, to provide a solar-cell apparatus having such terminal lead-out structure.
It is another object of the invention to provide a terminal lead-out structure having a hollow structure for the insulating protection of the electrode lead-out unit of an apparatus, wherein a series of extrusions are arranged on the surface of the hollow structure to face the apparatus to surround an electrode lead-out hole on the aforesaid surface, and a through hole is arranged on a surface other than the surface opposite to the apparatus for filling a filling agent in the hollow structure, and at the same time, the outer surface from the outer edge of the extrusions is adhesively bonded by an adhesive agent, and the filling agent is filled in the inner side from the inner edge of the extrusions for the insulating protection of the terminal lead-out structure, and also, to provide a solar-cell apparatus having such structure.
It is another object of the invention to provide a terminal lead-out structure having a hollow structure for the insulating protection of the electrode lead-out of the apparatus, wherein an extrusion is formed on the outer edge portion of the surface of the hollow structure to face the apparatus, and the extrusion is adhesively bonded to the apparatus by an adhesive agent, and also, to provide a solar-cell apparatus having such structure.
It is another object of the invention to provide a terminal lead-out structure having a hollow structure provided with a lead-out hole on the bottom thereof to lead out a lead line from an electrode lead-out unit, a lead-out hole on one side thereof to lead out an output cable, and an aperture on the top thereof, and with a lid member to cover the aperture, wherein the hollow structure is provided with extrusions on both sides adjacent to the aforesaid one side, and the lid member is provided with a flexible hook portion including recessed portions to engage with the extrusions, and also, to provide a solar-cell apparatus having such terminal lead-out structure.
It is another object of the invention to provide a terminal lead-out structure having a hollow structure provided with a lead-out hole on the bottom thereof to lead out a lead line from an electrode lead-out unit, a lead-out hole on one side thereof to lead out an output cable, and an aperture on the top thereof, and with a lid member to cover the aperture, wherein an extrusion is arranged on the fitting surface of the hollow structure and a recessed groove on the fitting surface of the lid member corresponding to the extrusion or a recessed groove is arranged on the fitting surface of the terminal lead-out box main body and an extrusion on the fitting surface of the lid member corresponding to the recessed groove, and further, a receiving portion is arranged on the terminal lead-out box main body to receive a flexible hooking portion, while making the width of the receiving portion equal to the width of the flexible hooking portion, and when the terminal lead-out box main body and the lid member, which are arranged in the recessed portion whose depth is equal to the thickness of the flexible hooking portion from the outer circumference of the hollow structure, are fitted together, the receiving portion is arranged to enable the outer surface of the terminal lead-out box and the outer surface of the flexible hooking portion to form a substantially flat surface, and also, to provide a solar-cell apparatus having such terminal lead-out structure.
It is another object of the invention to provide a terminal lead-out structure having a hollow structure arranged on the electrode lead-out unit of an apparatus for the insulating protection of the electrode lead-out unit, a lead line drawn from the electrode lead-out unit, an output lead line to connect the apparatus and another solar cell module, and a terminal unit to connect the lead line for use of leading out and the output lead line in the hollow structure, wherein the hollow structure is provided with a through hole arranged on the electrode lead-out unit, and the lead line for use of leading out is guided into the hollow structure by way of the through hole, while the terminal unit extruded from the inner wall of the hollow structure, and at the same time, the end portion of the extrusion thereof is fitted into a terminal stand through an aperture open inwardly on the terminal stand and a first screw inserted into the aperture thereof, and further, provided with a second screw to connect and fasten the terminal of the lead line for use of leading out and the terminal of the output lead line, and also, to provide a solar-cell apparatus having such terminal lead-out structure.
It is another object of the invention to provide a terminal lead-out structure fixed to an aperture by means of an adhesive agent to cover the output lead-out unit thereof, having a lead-out hole near the central portion of the bottom thereof to draw in the output lead line from the output lead-out unit, wherein a sticky adhesive agent is applied to the circumference of the output lead-out unit and the lead-in hole, and outside the sticky adhesive agent, the aforesaid adhesive agent is applied to fixing the terminal lead-out structure to the apparatus, and also, to provide a solar-cell apparatus having such structure.
It is another object of the invention to provide a terminal lead-out structure having a hollow structure provided with a hole on the bottom thereof to lead in the lead line drawn out from the electrode lead-out unit of an apparatus, and an aperture on the top thereof, and with a lid member to cover the aperture by fitting it with the hollow structure, wherein the hollow structure and the lid member are formed integrally by means of a hinge, and the hollow structure is provided with extrusions or recesses on the side opposite to the surface where the flexible hinge portion is arranged, while the lid member is provided with a flexible hooking portion including recesses or an extrusions to engage with the extrusions or the recesses, and the lid member is provided with a hooking portion on the bottom thereof to release the engagement between the extrusions and the recesses, and also, to provide a solar-cell apparatus having such terminal lead-out structure.
It is still another object of the invention to provide a solar-cell apparatus having a terminal lead-out structure and a cable used for electrical output, wherein the terminal lead-out structure is provided with a fixing member to fix the cable used for electrical output, and also to provide a terminal lead-out structure having a fixing member to fix the cable for use of electrical output.
It is a further object of the invention to provide a terminal lead-out structure having a hollow structure for the insulating protection of an electrode lead-out unit, and a filling agent to be filled in the hollow portion of the hollow structure, and also, to provide a solar-cell apparatus having such structure.
In accordance with the present invention, a solar cell module, which is provided with a weatherability film treated to discharge electricity as a surface coating material arranged at least on a part of the light receiving side, comprises a hollow structure for the insulating protection of a lead line drawn out from an electrode lead-out unit on the light receiving surface side of the solar cell module, and the electrode lead-out unit. Then, the interior of the hollow structure is filled with a filling agent.
It is preferable to use a hollow structure, which is arranged to be able to suppress the tension of a lead line, so as not to carry over the tension of the lead line to the electrode lead-out unit directly.
It may be possible to arrange a structure so that through holes are formed on a solar cell module and on a hollow structure, respectively, in order to fix the hollow structure on the solar cell module by fastening bolts and nuts applied to these through holes.
Also, it may be possible to arrange a structure to apply a sealing material between the outer frame of a hollow structure and a weatherability film.
Further, it may be possible to arrange a structure so that a hollow structure comprises a base portion and a covering portion, and then, a supporting unit is formed on the base portion in order to prevent the lead line from being pulled in the direction perpendicular to the light receiving surface of a solar cell module.
Here, as a surface coating material, a fluororesin film, both faces of which are treated to discharge electricity, is used, for example. Here, regarding the discharge treatment given to both faces of fluororesin, it is preferable to adopt a corona discharge process or sputtering process. Also, it is preferable to use a plastic material for the hollow structure in consideration of the electrical insulation, strength, water-proof capability, ease of handling, and weight, among other advantages. As a filling agent, it is also preferable to use adhesives of silicon rubber, epoxy resin or the like.
Also, in accordance with the present invention, the terminal lead-out structure of a solar cell module may be arranged with a hollow structure, which is provided with an extrusion at least on a part of the surface thereof to face the solar cell module. Here, the hollow structure may comprise a base portion and an upper covering portion.
More specifically, the hollow structure described above is a terminal box, for example. Therefore, the structure of the present invention is preferably usable for the surface of the terminal box of a solar cell module adhesively bonded with the solar cell module. In other words, the present invention is designed to apply its structure to a terminal box, and then, by adhesively bonding it with a solar cell module, it is intended to enhance the bonding operativity of a terminal box and the reliability of resultant adhesion as well.
Also, in accordance with the present invention, the terminal lead-out structure of a solar cell module may be arranged so that a hollow structure is provided with a series of extrusions on a surface thereof to face the solar cell module to surround an electrode lead-out hole arranged on the aforesaid surface, and then, a through hole is arranged on a surface other than the aforesaid surface to fill a filling agent in the hollow structure, and that the outer surface is adhesively bonded from the outer edge of the extrusions, and at the same time, the filling agent is filled in the inner side from the inner edge of the extrusions for the insulating protection of the electrode lead-out unit.
In this case, it is preferable to make the viscosity of adhesives more than 300 poise when applied to bonding the solar cell module and the hollow structure. Also, it is preferable to make the viscosity of the filling agent less than 1,000 poise, when filling the filling agent in the inner side from the inner edge of the extrusions for the insulating protection of the electrode lead-out unit.
Usually, in this respect, at least one through hole is arranged for the electrode lead-out unit of a solar cell module on the surface of the hollow structure to face the solar cell module.
For the structure described above, it is preferable to use a plastic material for the hollow structure in consideration of the electrical insulation, strength, water-proof capability, ease of handling, and weight among some other advantages. For the adhesive agent, it is preferable to use adhesives of silicone, silane, epoxy resin or some others.
Also, in accordance with the present invention, the terminal lead-out structure of a solar cell module may be provided with a hollow structure having an extrusion on the outer circumference of the surface thereof to face the solar cell module.
Here, the hollow structure comprises a base portion and an upper covering portion, and may be structured to form an extrusion on the base portion. Also, the extrusion and the solar cell module may be bonded by use of a double-coated adhesive tape, for example. Further, as described above, the base portion can be bonded to the solar cell module more reliably by use of the filling agent whose viscosity is less than 1,000 poise, which is filled in the hollow structure.
Also, for a solar cell module, a terminal lead-out box is fixed to the output lead-out unit on the reverse side thereof by use of silicone resin, epoxy resin, or the like, and then, the output lead lines of positive pole and negative pole are drawn out from the terminal lead-out box. For the terminal lead-out box, there are a single type terminal lead-out box and a terminal lead-out box with a cover comprising the terminal lead-out box main body and its lid member. These boxes have its advantages and disadvantages, of course.
The former is advantageous in its cost aspect because of the simpler structure, but it may lack the capability of maintenance such as replacement and checking of cables after installation. On the other hand, the latter makes it possible to perform the replacement of cables and others, although costs are higher. It is advantageous over the former in the long run.
For the terminal lead-out box with a lid member, a rubber packing or some other water-proof material is often included between the terminal lead-out box main body and the lid member in order to obtain its water-proof capability when fitting the terminal lead-out box and the lid member together.
Also, the box of this type uses screws, keys, pins, or some other components to fit the lid member and the terminal lead-out box main body for fixation in some cases.
Also, a terminal box of the kind described above is often fixed to the reverse side of a solar cell module by use of adhesives of silicone, silane, or the like. When the box is fixed to the reverse side, an extruded portion is present on the reverse side of the solar cell module. Therefore, it becomes impossible, particularly for a frameless solar cell module, to be installed on a flat location. It is preferable to make a special arrangement so that the design of the module is not spoiled if the installation allows the reverse side of the module to be observable by eye sight.
Besides, there are cases where the screw fastening type is used, which is high in the mechanical and electrical reliability with respect to the terminal lead-out structure in the interior of a terminal box. The lead line drawn out from the electrode lead-out unit of a solar cell module is connected through this structure with the output lead line that connects solar cell modules electrically.
However, as shown in FIG. 1, the terminal lead-out structure of a screw fastening type used for a terminal box 104 is such that the lead line 101, which is drawn out from the electrode lead-out unit of a solar cell module, is soldered to plate type conductor 102 having a plurality of holes. The external lead lines are fixed to the conductor 102 by means of screw fastening. As a result, there is the need for the provision of the screw fastening portions to fix the screws. In order to form the female screw portions, insert metals should be pressed in or thermally bonded, or by means of a combination of press-in and expansion, among some others means. For the construction of such terminal structure, it is necessary to prepare a conductor of a desired plate configuration in advance. Such conductor should be fixed as required. Also, in order to insert the insert metal 103, the insert metal should be warmed beforehand among some other routines. Therefore, it takes a considerable time for such operation in some cases. Further, it is necessary to make each boss thicker at the inserting position of the insert metal 103. This arrangement may require a space more than necessary.
Also, as shown in FIG. 2, when a terminal stand for general use is adopted, a screw fastening, a thermal bonding, or some other operation is necessary to fix the terminal stand 201 to the terminal box 202 or there is a need for the provision of a hooking nail or the like to hook the terminal stand 201. Further, a comparatively small terminal stand 201 for general use is designed and produced in anticipation of its main use for a printed circuit board or the like. As a result, screw holes or others are provided for installation, which requires an extra space to that extent in a terminal box 202 in some cases. Also, on the bottom of a terminal box 202, or separately, a terminal stand is needed, thus making costs higher accordingly.
Such being the case, it is preferable to arrange the terminal structure in consideration of all the aspects discussed above.
Also, for a terminal lead-out box, there are some cases where a lead-in hole for drawing in the output lead line, and a lead-out hole for drawing out the output lead-out conductor should be arranged.
Through the lead-in hole, the output lead line of either positive pole or negative pole is drawn in, while through the lead-out hole, the output lead-out conductor, which is connected to the output lead line in the terminal lead-out box, is drawn out.
The installation method of this terminal lead-out box is often such that the terminal lead-out box is fixed to the output lead-out unit by means of adhesives, such as silicone resin or epoxy resin, and then, the output lead-out conductor and others are installed after the drying process of the adhesives.
For the operation of applying adhesives to the terminal lead-out box and fixing it by pressure, a skilled work and other routines are needed to a certain extent in order to obtain the uniformity in this respect.
Meanwhile, there is an installation method that uses a sticky adhesive agent in place of an adhesive agent, which requires no drying process, and contributes to improving operativity.
Here, in accordance with the method for installing the terminal lead-out box by use of adhesives, there is a need for a process to dry the adhesives used as described above. For that matter, an operation to move to a site where adhesives can be dried, an operation to secure such site, and others are required, thus incurring a great amount of expenditures in executing such operation in some cases.
Also, for the installation by use of adhesives, the finished thickness of adhesives varies depending on application of pressure as described earlier, besides other difficulties to obtain a uniform operativity. In order to make the finished thickness uniform, a constant application of pressure and other skilled work is necessary.
On the other hand, the installation by use of only a sticky adhesive agent has an advantage in improving such operativity because this agent provides an initial adhesive power. However, there is still a problem that the adhesive power is lowered at a high temperature and humidity, among other problems related to its reliability in some cases.
Also, when a terminal box is fixed to a solar cell module by the application of adhesives, the varied pressure exerted on the terminal box does not allow the adhesives to spread over the adhesive surface sufficiently or if such pressure is too strong, the thickness of the adhesives is made thinner, hence lowering the resultant adhesive power depending on the way bonding operation has been carried out.
Also, in a state in which a terminal box is bonded to a solar cell module as it is, the outer appearance becomes unfavorable in some cases, because adhesives flow out from the outer circumference of the terminal box. In this case, if the adhesive agent that flows out is left intact, it is exposed to the direct or scattered light of the sun, resulting in a conspicuous deterioration of its performance in some cases. Also, to wipe off the flowing out adhesive agent requires a skilled worker. In this case, the adhesive agent applied between the terminal box and the solar cell module is even wiped off as the case may be.
Therefore, it is more preferable to design the terminal lead-out structure in consideration of such unfavorable operativity resulting from the use of adhesives, the insecure reliability to ensue, and other related events.
Also, for a terminal lead-out box with a lid member, if a screw fit is adopted, a structure is arranged to fasten a male screw and press-in nut, helical inserting member, or a tapped female screw. When a key, a pin, or the like is used for fitting, too, there is a need for the provision of elements other than the terminal lead-out box main body and the lid member. Therefore, a problem of higher costs is encountered in some cases. Also, when a module is installed with a covered terminal lead-out box in it, the operativity is unfavorable at the time of checking and others. Further, in case of a screw fitting, attention should be given even to the fastening torque and others, which may result in unfavorable operativity. On the other hand, these fitting operations can be made by anybody and the disengagement of the fittings is also the same. Therefore, mischievous or careless conduct may be committed. There is even a fear that the fitting is not carried out exactly as anticipated.
Meanwhile, regarding the water-proof capability of a terminal lead-out box with a lid member, an arrangement is made to secure it by fitting the terminal lead box and the lid member with inclusion of a rubber packing or some other water-proofing material between them. The provision of a water-proof material, such as a rubber packing, brings about an extra cost. Therefore, not only a problem of increased costs is encountered, but also, in some cases, the water-proof capability of such material as a rubber packing is lowered due to the fitting pressure exerted between the terminal lead-out box main body and the lid member, as well as due to the aging of the water-proof material itself.
Also, the terminal lead-out box with a lid member comprises different components, a terminal lead-out box main body, and a lid member. A problem of operativity may take place like loss of lid members in some cases.
Therefore, it is preferable to design a terminal lead-out structure in consideration of the increased costs, the lowered water-proof capability, and the improvement of operativity as referred to in the preceding paragraphs.
Now, regarding the solar cell module integrally formed with a roofing material, developments and studies are being made with respect to the solar cell module that fits to the conventional roofing operation as given below. Such developments and studies are those represented in FIG. 3 and FIG. 4, for example.
FIG. 3 is a cross-sectional view showing a solar cell module 24. FIG. 4 is a perspective view showing the solar cell module represented in FIG. 3, observed from its rear side. This solar cell module is provided with a metallic reinforcement plate 13 on its rear side. The solar cell module 24 is sealed by means of a surface film 15 and a light transmitting resin 16. Both edge portions 17 of this kind of solar cell module 24 are folded upward at an angle of 90xc2x0 on its longer side so as to fit it to the usual process of tiled roofing.
To the metallic reinforcement plate 13, the base member 22 of a terminal lead-out box 18 is adhesively bonded by use of silicon adhesive agent 19. An electric output cable 20 is provided for it together with a bushing 21. Further, a lid member 23 is installed. In this case, the terminal lead-out box 18 is fabricated so as to enable the fitting portion of the base member 22 and the lid member 23 to be water proofed. Further, by use of the bushing 21, water-proofing is maintained at the cable lead out portion. For a solar cell module integrally formed with a roofing material, it is preferable to be able to execute electrical wiring when installing the module. Therefore, a one-touch connector 40 is mounted on the leading end of the electric output cable 20 of the solar cell module described above. The length of the cable is also set at a length easy to handle (30 cm, for instance).
This way, a desired electric output cable 20 for use of electrical output and a one touch connector 40 are provided for a solar cell module from the outset, thus making it easy to operate the required electric wiring at the time of installation of the solar cell module 24.
Nevertheless, in accordance with the solar cell module described above, the electric output cable hangs down from the rear side thereof. Consequently, at the time of post-processing of a solar cell module, and also, at the time of transporting it for installation, this setup may impede an easier handling of the solar cell module.
In other words, both end portions 17 of the solar cell module described above are folded upward at an angle of 90xc2x0 on its longer side. However, at the time of operating this folding as one of post-processes, it may become difficult to execute such process if the cable hangs down on the rear side of the solar cell module.
The folding is gradually executed by use of an apparatus, the so-called roller making machine, while each solar cell module is continuously conveyed for the intended processing.
The processing method by use of a roller 25 making machine is such that, as illustrated by the cross-sectional view in FIG. 5, each solar cell module is pinched by the upper and lower carrier rollers 26 to convey it. Here, the configurations of processing rollers 25, which are in contact with the folding portions, are formed so that the solar cell module is folded in a shape as shown in FIG. 3 ultimately. In this respect, a plurality of stations are arranged to provide the processing rollers whose configurations gradually change, hence folding the solar cell module to the final configuration as described above through one section after another.
However, as clear from FIG. 5, if the electric output cable 20 is in a state of handing down as it is, there is a possibility that it gets entangled in the roller making machine. Hence, the process cannot be executed as anticipated. Therefore, each electric output cable 20 is fixed to the metallic reinforcement plate by means of an adhesive tape 28 as a countermeasure in this instance.
Now, a brief description will be made of the reason why the folding process is executed after the installation of the terminal lead-out box and cable as a sequence of fabrication process, and also, why the installation of the terminal lead-out box and cable is not intended on the contrary, that is, why not before the execution of folding process.
If it is intended to execute the operation of adhesive bonding of a terminal lead-out box to a solar cell module that has been already folded, the module tends to be warped or present unstable conditions making it difficult to execute such operation. Here, therefore, a fixture should be prepared so that the module is held horizontally at a height more than the height of the folded portions, and then, the intended adhesive bonding operation is carried out after the module is placed on such a fixture. The operation becomes complicated inevitably.
Also, in order to dry a sealant agent, the module should be placed so that the terminal lead-out box side is placed upward, and kept horizontally at room temperature for 24 hours as it is. Therefore, as described earlier, the module that has already been folded should be placed on a stand dedicated to keeping it horizontally so as not to cause it to warp. However, if a module is already folded, the volume that one module occupies becomes larger to that extent. The space occupied by modules to keep them for drying the sealant agent becomes extremely greater than the one needed for the modules yet to be folded. Now, in consideration of these aspects, it is more suitable that the installation of the terminal lead-out box should be carried out before the folding process is executed.
Now, when the solar cell module is transported to the site of its installation, it is extremely dangerous if each cable hangs down from the module, because it may be hooked unexpectedly. Each of the cables should be fixed by means of an adhesive tape so as not allow it to hang down.
However, if each of the cables is fixed by means of an adhesive tape, such tape should be peeled off last, immediately before the intended installation and wastefully discarded eventually.
Also, the installation operator is often troubled in disposing of the tape thus peeled off, because many solar cell modules are carried over to the site of installation where it is executed.
Further, for the safety, the operators wear gloves, thus making it difficult to peel off the adhesive tapes. Here, the peeled off tapes are still sticky and may present an obstacle in operating the installation smoothly in some cases, because the tapes adhere to his gloves.
Such being the case, the use of adhesive tapes for fixing each of the cables presents a number of problems as described above. Conceivably, therefore, it is possible to use clamps available on the market. For example, as shown in FIG. 6, a clamp 44 is fixed to the metallic reinforcement plate by means of a double-coated adhesive tape, thus fixing the cable 20 in place. With this method, it is possible to avoid such a troublesome case as just using the adhesive tapes.
Nevertheless, the clamp 44 is still discarded at the end because it is no longer needed. Here, the double-coated adhesive tapes, clamps, and each step of adhesive processes are extremely wasteful in cost. At present, therefore, it is inevitable to adopt the method that uses adhesive tapes to fix each of the cables.
Aside from the problems described above, there is a problem that a connector cannot be mounted easily due to the winding habit of a cable acquired when it is fixed to a module. When an installation is executed in a cold site during the winter, the temperature of the operational environment is extremely low. Then, the flexibility of covering material of cable is lost, making it extremely difficult to fix each the connector against its winding habit thus acquired. Therefore, if the cable is fixed to the module in a configuration in which no consideration is given to such winding habit that the cable may acquire, the operation becomes extremely difficult when the module is installed.
This situation will be described briefly in conjunction with FIG. 7. FIG. 7 is a view showing a state of solar cell modules being installed, which is observed from its rear side. As shown in FIG. 7, it is assumed that a solar cell module 24a is installed on the ridge side of a roof, while another solar cell module 24b is installed on the eaves side thereof. These modules are installed with a superposed portion 43 as flashing. In this case, if the cables and connectors are fixed to the rear sides of modules by means of tapes 28, respectively, the positive and negative connectors 40a and 40b should be connected, while deforming them against the winding habit of each of them as indicated by broken lines partly showing the locus of deformation process of each cable. This work is not easy for the operator to handle, because he is required to exercise much of his physical strength.
It is not so easy to handle a cable itself that has lost its flexibility, while having such winding habit. In addition to it, there are the reasons given below, which makes the operation more difficult.
The configuration of winding habit that each cable of positive or negative pole has acquired is an axial symmetry with respect to line a-axe2x80x2. It remains being axially symmetrical when both the cable and connectors are deformed. On the other hand, the connectors should rotate at an angle of more than 270xc2x0 from the state of being fixed before these connectors can face to engage with each other. Therefore, if the cables have lost flexibility, the operation may require an enormous amount of strength just before mounting both connectors after causing them to have rotated more than 270xc2x0.
Such being the case, it is very important to give attention also to the connectivity of cables from the viewpoint of providing reliability and operativity.